standard

        input = ""              Input image file root name
       output = "std"           Output flux file (used by SENSFUNC)
    star_name = leave blank     Star name in calibration list
      airmass = header          Airmass
      exptime = header          Exposure time (seconds)
          mag =                 Magnitude of star
      magband =                 Magnitude type
         teff =                 Effective temperature or spectral type
       answer = "no"            (no|yes|NO|YES|NO!|YES!)
    (samestar = yes)            Same star in all apertures?
 (beam_switch = no)             Beam switch spectra?
   (apertures = "")             Aperture selection list
   (bandwidth = INDEF)          Bandpass widths
     (bandsep = INDEF)          Bandpass separation
     (fnuzero = 3.6800000000000E-20) Absolute flux zero point
  (extinction = "onedstds$ctioextinct.dat")  Extinction file
      (caldir = "/astro/users/ben/premap/calibration/fluxcal/")               Directory containing calibration data
 (observatory = "ctio") Observatory for data
    (interact = yes)            Graphic interaction to define new bandpasses
    (graphics = "stdgraph")     Graphics output device
      (cursor = "")             Graphics cursor input
        (mode = "ql")           

IMPORTANT NOTES:

IRAF will search the directory specified by keyword caldir to find a 
list of standard star tables and prompt the user to pick  the table
applicable to the star actually observed. It is very important to 
specify caldir exactly as above, i.e., with a / at the end of the 
path. 

The keword star_name specifies the table that the task should use.
If the file name is known, it can be entered here, otherwise the 
entry can be left blank so that the program will prompt the user to
enter the file name after inspecting the list of available files.

Keywords marked as header should be left blank so that the task can
get that information from the data header.